Sound reducing cover seal for information recording apparatus

This is a divisional application of application Ser. No. 09/127,215, filed Jul. 31, 1998, now U.S. Pat. No. 6,266,207, issued Jul. 24, 2001.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an information recording apparatus such as a hard disk drive unit (HDD), and more particularly, to a cover seal covering over a seam provided between an edge around an opening of a housing and a cover for closing the opening.

The term “seam” is referred to in this specification as a portion between the edge and the cover, with or without a gap therebetween.

2. Description of the Prior Art

It is well known that an HDD employs a cover of a vibration suppression metallic plate so as to reduce noise during reading/writing operation for data. The cover is coupled to a housing body of a box-shape in the HDD for providing a housing. The housing of this type may contribute to reduction in noise by the effect of the vibration suppression metallic plate.

A housing of an HDD should air-tightly enclose a magnetic disk and a magnetic head. For example, in case where a housing is comprised of a pair of members such as a box-shaped housing body and a cover of a vibration suppression metallic plate, a cover seal is adhered to air-tightly close the opening of the housing body. The housing body and cover seal serve to enclose the cover, so that a seam between the housing body and cover is sealed. Since the cover seal can contribute to cost reduction as compared with a packing, the cover seal comes to take the place of the packing as a seal member.

The present inventors have discovered that air flows in the seam between the housing body and cover so that the air causes the cover seal to vibrate during reading/writing operation for data. The present inventors have confirmed that the vibration of the cover seal takes part in noise of the HDD.

SUMMARY OF THE INVENTION

It is accordingly an object of the present invention to provide a cover seal for an information recording apparatus capable of reducing noise of the apparatus.

According to a first aspect of the present invention, there is provided a cover seal comprising: a metallic sheet; and an adhesive layer formed on a side face of the sheet for adhering the sheet on a housing for an information recording apparatus.

The rigidity of the cover seal may be reinforced by the metallic sheet, so that the cover seal can be prevented from vibrating. Accordingly, noise caused by vibration of the cover seal can be reduced. The metallic sheet of the cover seal may be covered with a protection layer of a synthetic resin.

The cover seal is employed in an information recording apparatus. The information recording apparatus may comprise a housing body accommodating at least a recording disk and a head, and a cover plate closing an opening of the housing. The metallic sheet of the cover seal preferably covers over at least a seam between an edge around the opening and the cover. The adhesive layer of the cover seal serves to adhere the metallic sheet on the edge and a surface of the cover. Accordingly, even if air stream in the seam acts on the cover seal from the back, the cover seal can be prevented from vibrating, so that the generation of noise can be suppressed. The cover seal may cover all over the cover so as to enclose the cover in the housing body and the cover seal itself.

According to a second aspect of the present invention, there is provided a cover seal comprising: a multilayer synthetic resin sheet having an interposed adhesive layer; and an adhesive layer formed on a side face of the sheet for adhering the sheet on a housing for an information recording apparatus. The multilayer structure may reinforce the rigidity of the cover seal, so that the same effect as the first aspect can also be achieved.

It should be noted that an information recording apparatus employing the cover seal according to the first or/and second aspect may be installed in a computer apparatus, or, may be constructed as a stand-alone exterior recording apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the present invention will become apparent from the following description of the preferred embodiment in conjunction with the accompanying drawings, wherein:

FIG. 1 is a block diagram schematically illustrating the structure of a computer apparatus;

FIG. 2 is an exploded perspective view of a hard disk drive unit (HDD);

FIG. 3 is an enlarged partial view illustrating the section taken along the line <b>3</b>—<b>3</b> in FIG. 2;

FIG. 4 illustrates the structure of a cover seal according to a first embodiment of the present invention; and

FIG. 5 illustrates the structure of a cover seal according to a second embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 schematically illustrates the structure of a computer apparatus CO. The computer apparatus CO comprises a computer unit <b>13</b> assembled with a central processing unit (CPU) <b>11</b>, and a hard disk drive unit (HDD) <b>12</b> as an information recording apparatus of the present invention. The CPU <b>11</b> is capable of sending and receiving information data to and from the HDD <b>12</b> in accordance with instructions input from an input device <b>14</b>, such as a keyboard and/or a mouse, which is connected to the computer unit <b>13</b>. The information data may be displayed on a screen of a display device <b>15</b> which is connected to the computer unit <b>13</b>.

FIG. 2 illustrates an exploded perspective view of the HDD <b>12</b>. As shown in FIG. 2, the HDD <b>12</b> comprises a box-shaped housing body <b>20</b> as a member of a housing <b>19</b>. The housing body <b>20</b> is for example formed by aluminum die-casting into a box-shape so as to have a high rigidity.

The housing body <b>20</b> accommodates a plurality of magnetic disks <b>21</b> as recording media for recording information data, and magnetic heads <b>22</b> as reading/writing means opposed to the disk surfaces of the respective recording disks <b>21</b>. The recording disks <b>21</b> may rotate about a rotation axis <b>24</b> fixed to the housing body <b>20</b>. The rotation of the disks <b>21</b> is driven by a spindle motor, not shown. A carriage <b>25</b>, with the magnetic head <b>22</b> at the tip end, may swing about a carriage axis <b>27</b> fixed to the housing body <b>20</b>. The swinging movement of the carriage <b>25</b> is caused by a magnetic circuit <b>26</b> comprising an actuator. The magnetic heads <b>22</b> are positioned to a target recording track and block through the rotation of the disks <b>21</b> and the swinging movement of the carriage <b>25</b>.

A cover plate <b>30</b> closes a housing opening <b>29</b> of the housing body <b>20</b>. The cover <b>30</b> is coupled to the housing body <b>20</b>, by screws <b>31</b> positioned at four corners of the cover <b>30</b>, so as to form the housing <b>19</b>. Screw receiving recesses <b>32</b> are formed at the corners of the cover <b>30</b> so as to prevent the heads of the screws <b>31</b> from protruding from the level of the surface of the cover <b>30</b>. Steps <b>34</b> are formed on the housing body <b>20</b> inside a housing edge <b>33</b> at the corners for receiving the screw receiving recesses <b>32</b> of the cover <b>30</b>. When the steps <b>34</b> receive the screw receiving recesses <b>32</b>, the surface of the cover <b>30</b> is leveled with the housing edge <b>33</b>. Moreover, the heads of the screws <b>31</b> are prevented from protruding from the surface of the cover <b>30</b>.

When the cover <b>30</b> is coupled to the housing body <b>20</b>, two connecting screws <b>35</b> are screwed into the tip ends of the rotation axis <b>24</b> and the carriage axis <b>27</b>. Connecting screw receiving recesses <b>36</b> are formed in the cover <b>30</b> so as to prevent the heads of the connecting screws <b>35</b> from protruding from the level of the surface of the cover <b>30</b>.

The cover <b>30</b> may be formed by a press from an aluminum plate or a vibration suppression metallic plate. The press shapes the screw receiving recesses <b>32</b> and the connecting screw receiving recesses <b>36</b> on the cover <b>30</b>. The vibration suppression metallic plate may be a VEM comprising a vibration suppression material layer such as synthetic resin layer interposed between a pair of steel sheets.

When the attachment of the cover <b>30</b> is completed, a cover seal <b>38</b> is adhered to the outer surface of the housing <b>19</b>. The cover seal <b>38</b> not only covers all over the surface of the cover <b>30</b> as is apparent from FIG. 2 but also extends to the edge <b>33</b> of the housing body <b>20</b> as shown in FIG. <b>3</b>. Accordingly, a seam <b>39</b> between the edge <b>33</b> and the cover <b>30</b> is air-tightly sealed by the cover seal <b>38</b>. When the cover seal <b>38</b> is,adhered all along the edge <b>33</b>, the cover <b>30</b> is enclosed in the cover seal <b>38</b> and the housing body <b>20</b>. The heads of the screws <b>31</b> in the screw receiving recesses <b>32</b> and the heads of the connecting screws <b>35</b> in the connecting screw receiving recesses <b>36</b> are positioned inside the cover seal <b>38</b>.

FIG. 4 illustrates the structure of a cover seal <b>38</b><i>a </i>according to a first embodiment of the present invention. The cover seal <b>38</b><i>a </i>comprises a metallic sheet <b>41</b> and an adhesive layer <b>42</b> formed on a rear face of the sheet <b>41</b>. The metallic sheet <b>41</b> may have rigidity enough to keep its shape by itself. The sheet <b>41</b> is for example made of an aluminum film or a copper film. The adhesive layer <b>42</b> serves to adhere the metallic sheet <b>41</b> on the cover <b>30</b> and the edge <b>33</b> of the housing body <b>20</b>. A PET (polyethylene terephthalate) protection layer <b>43</b> is formed on the front face of the metallic sheet <b>41</b> as a protection layer of a synthetic resin. The protection layer may be made from other synthetic resin in place of PET.

Assume that air stream <b>45</b> flows in the seam <b>39</b> between the housing body <b>20</b> and the cover <b>30</b> shown in FIG. <b>3</b>. The air stream <b>45</b> acts on the rear surface of the cover seal <b>38</b>. However, the cover seal <b>38</b> reinforced by the rigidity of the aluminum or metallic sheet <b>41</b> is prevented from vibrating, so that noise transmitted to the outside can be reduced. According to an experiment managed by the present inventors, the employment of the cover seal <b>38</b><i>a </i>achieves the noise level of 39 dB, while a conventional cover seal comprising a PET layer of 50 micrometers thickness and an adhesive layer of 30 micrometers thickness achieves the noise level of 41 dB. The cover seal <b>38</b><i>a </i>in the experiment has an aluminum or metallic sheet <b>41</b> with thickness b=50 micrometers, an adhesive layer <b>42</b> with thickness c=50 micrometers, and a PET protection layer <b>43</b> with thickness a=28 micrometers, as shown in FIG. <b>4</b>. The PET protection layer includes an adhesive layer of 5 micrometers for adhering the PET protection layer <b>43</b> to the aluminum or metallic sheet <b>41</b>.

The description will be made for a manufacture process of the cover seal <b>38</b>a referring to FIG. <b>4</b>. First of all, an aluminum sheet <b>41</b> is prepared and predetermined characters may be printed on a surface of the sheet <b>41</b>. An adhesive and a PET sheet are then placed on the printed surface of the sheet <b>41</b>. When heat and pressure are applied with a heat roller to the printed surface, a PET protection layer <b>43</b> is formed on the sheet <b>41</b>. An adhesive layer <b>42</b> is then applied to the rear surface of the sheet <b>41</b> by using a roller or the like. A peel sheet is attached to the rear surface over the applied adhesive layer <b>42</b>. The cover seal <b>38</b><i>a </i>can be punched out of the sheet <b>41</b>. In use, the peel sheet is peeled off and the cover seal <b>38</b><i>a </i>is placed on a surface of the housing <b>19</b> with the adhesive layer <b>42</b> facing the surface.

As shown in FIG. 2, an inspection hole <b>44</b> may be bored in the cover seal <b>38</b><i>a</i>. A communication hole <b>30</b><i>a </i>is formed in the cover <b>30</b> corresponding to the inspection hole <b>44</b>. These inspection hole <b>44</b> and communication hole <b>30</b><i>a </i>can be used when the air-tightness of the housing <b>19</b> is examined. Specifically, the examination can be conducted by first blowing air into the housing <b>19</b> through the inspection hole <b>44</b> and communication hole <b>30</b><i>a </i>and then detecting a leakage of air from the periphery of the cover <b>30</b> and the vicinity of the screws <b>31</b> and the connecting screws <b>35</b>. The communication hole <b>30</b><i>a </i>may be sealed by a seal member after the examination. The examination may be conducted during or after the assembling process of the HDD <b>12</b>.

FIG. 5 illustrates the structure of a cover seal <b>38</b><i>b </i>according to a second embodiment of the present invention. The cover seal <b>38</b><i>b </i>comprises a multilayer synthetic resin sheet <b>46</b> and an adhesive layer <b>47</b> formed on a rear surface of the synthetic resin sheet <b>46</b>. The rigidity of the synthetic resin sheet <b>46</b> is reinforced by a pile of first and second synthetic resin sheets <b>48</b>, <b>49</b> with an adhesive layer <b>50</b> interposed therebetween. The first and second synthetic resin sheet <b>48</b>, <b>49</b> may be made from PET material. The adhesive layer <b>47</b> serves to adhere the multilayer synthetic resin sheet <b>46</b> on the cover <b>30</b> and the edge <b>33</b> of the housing body <b>20</b>.

According to an experiment managed by the present inventors, the employment of the cover seal <b>38</b><i>b </i>achieves the noise level of 40 dB, while a conventional cover seal comprising a PET layer of 50 micrometers thickness and an adhesive layer of 30 micrometers thickness achieves the noise level of 41 dB. The cover seal <b>38</b><i>b </i>in the experiment has a first synthetic resin sheet <b>48</b> with thickness d=50 micrometers, a second synthetic resin sheet <b>49</b> with thickness f=50 micrometers, an adhesive layer <b>50</b> with thickness e=30 micrometers, and an adhesive layer <b>47</b> with thickness g=30 micrometers.